This invention relates to data communication and, more particularly, to a digital data communication system capable of high-speed data transfer with low power disipation.
In this age of microelectronics, thousands of electronic circuits can be incorporated in a single integrated circuit "chip", and many chips can be mounted on a single printed circuit board. Advances are being made to further miniaturize electronic systems and to reduce the power dissipated by such systems. The interconnections between integrated circuit chips on a printed circuit board functions as transmission lines in that they have distributed resistance, capacitance, and inductance, because of their interconnection length relative to the signal edge transition time of the waveform. As a result, usual transmission line considerations, such as impedance matching and power dissipation are major concerns in the design of inter-chip connections.
Conventionally, voltage mode circuitry is employed to transfer digital data between integrated circuit chips. To increase the data transmission speed, a high price must be paid in terms of power dissipation, because of the large voltage swing that must be repeatedly imposed on the inter-chip connection and the transmission line matching requirements. For example, to transmit data at a rate of 500 megabits per second, power dissipation of the order of 100 milliwatts per bit must be incurred.